Admission Inflammatory Blood Cell Ratios as Prognostic Markers of Functional Outcome After Aneurysmal Subarachnoid Hemorrhage: A Single-Center Retrospective Cohort Study

Background/Objectives: Early functional status at hospital discharge is a clinically relevant outcome after aneurysmal subarachnoid hemorrhage (aSAH), but early prognostic assessment remains challenging. We evaluated whether admission inflammatory blood cell ratios were associated with discharge independence and added prognostic information beyond established neurological severity scales. Methods: In this retrospective single-center cohort study, 252 consecutive adults with aSAH were screened, and 144 endovascularly treated patients with available admission complete blood count with differential were included. Discharge independence was defined as a Barthel Index score ≥60 at hospital discharge. A clinical reference model included age, World Federation of Neurosurgical Societies (WFNS) grade, and Hunt–Hess grade. Multivariable logistic regression was used to assess associations between inflammatory ratios and discharge independence. Discrimination was assessed using receiver operating characteristic analysis with DeLong’s test, and the final model was internally validated by bootstrap resampling. Results: Forty-one patients (28.5%) achieved discharge independence. Higher admission neutrophil-to-lymphocyte ratio (NLR) was independently associated with lower odds of discharge independence (adjusted odds ratio 0.47 per interquartile range increase, 95% CI 0.24–0.90; p = 0.022). Adding NLR to the clinical reference model improved discrimination (AUC 0.790 vs. 0.737; p = 0.039), with an optimism-corrected AUC of 0.767 after bootstrap validation. Other inflammatory indices did not significantly improve discrimination. Conclusions: In this single-center retrospective cohort of endovascularly treated patients with aSAH, admission NLR was independently associated with discharge independence and provided modest incremental prognostic information beyond established neurological severity scales.